In a magnetic disk drive, typically a hard disk drive, side fringe (influence of a leakage magnetic field over a magnetic recording medium) may be a cause of data erase in adjacent tracks. To counter this, track refresh by rewriting recorded data has been adopted. If power is shut down during a write operation in the track refresh, a write splice caused by the power shutdown (a redundancy area for a signal to settle to an active level: write-joint) is occurred, and a sector which cannot be read is remained.
In order to avoid the above problem, when track refresh is performed, at first data is saved in a temporary storage area and then the data sector is rewritten. However, since the temporary storage area exists at a specific part of the recording medium, this technique entails a seek operation to reach the temporary storage area. Consequently, it takes a long time to perform the refresh operation, and the performance of the magnetic disk drive is thereby degraded.